Interlining is used in clothe-making whenever part of a garment requires stiffening, such as for example a shirt collar. Conventional methods have heretofore implied placing a specially finished cotton cloth, called buckram, between the two pieces composing the collar. But with wear, and in particular after repeated washes, the collar was often found to be deformed due to a different behavior of the pieces composing it, and even due to a displacement of the buckram inside the collar. One solution found to overcome this drawback has been to bond the reinforcing element to the article to be reinforced. Also, the finished cotton cloth being quite expensive when it is not actually seen, a solution has been to replace it with a nonwoven which is a cheaper product.
The nonwovens used as interlinings contain either a bonding agent, in the case of small stiffening pieces such as for stiffening the collar of a shirt or a blouse, or thermal bonding fibers in the case of complete interlining of women's clothes and raincoats. A bonding by thermo-fusible fibers is described, for example, in U.S. Pat. No. 4,373,000. A nonwoven interlining bonded by the melting of thermo-fusible fibers is more supple and more textile to the touch than a nonwoven interlining bonded with a binding agent.
It has however been found that another problem arises when using nonwovens as thermo-bonding interlining base. The dots of resin deposited on the nonwoven for bonding the interlining to the underside of the textile piece to be stiffened should not go through the interlining as this would risk to tighten up the said piece or even to stick the interlining to the lining.
Various solutions have been proposed to overcome this problem, the simplest one being the use of nonwovens having a high weight per square meter, generally higher than 150 g, but such weight affects the qualities of the interlining in certain fields of application. Another solution consists, before applying the thermo-bonding resin, in making a first coating designed to prevent the spreading of the resin when pressure is applied; this solution, however, is difficult to implement and noticeably increases the cost of the interlining.